1. Field of the Invention
The present invention relates to semiconductor devices and, in particular, relates to a semiconductor device having an input receiver circuit to acquire an input signal in synchronization with a strobe signal.
2. Description of Related Art
With a semiconductor device executing high-speed data transfer such as DRAM (Dynamic Random Access Memory), input/output of a data signal may be performed in synchronism with a strobe signal (see Japanese Patent Application Laid-open No. 2001-312886). Meanwhile, an input receiver circuit that receives an input data signal often has the structure to generate an output signal by comparing a potential of the input data signal with a reference potential.
However, a change in the strobe signal may cause noise in the reference potential. When the noise is superimposed on the reference potential, an operating margin of the input receiver circuit decreases, which makes the high-speed data transfer difficult.
Such a difficulty becomes serious especially when the reference potential is generated inside a semiconductor device. Further, such a difficulty becomes more serious especially when the input receiver circuit that is activated by the strobe signal is employed. Furthermore, such a difficulty becomes even more serious especially when the strobe signal is generated by complementary external strobe signals that are supplied from the outside and potential of the external strobe signals is fixed to a high level or a low level during a period when the input data signal is not supplied thereto.